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Notes: Abstract Atriplex amnicola was grown at 25, 200 or 400 mol m3 NaCl. Root tissues at different stages of development were investigated for concentrations of K+, Na+ and Mg2+, and in some cases for Cl−. Sugar and starch concentrations were measured for plants grown at 25 or 400 mol m3 NaCl.In the ‘slightly vaeuolated’ root tips, Na+ was only 40 mol m−3 at an external concentration of 400 mol m−3 NaCl. The concentrations of K+ were not affected substantially by external NaCl between 25 mol m−3 and 400 mol m−3. The ‘highly vacuolated’ root tissues had substantially higher concentrations of K+, Na+ and Cl− in plants grown at 200 and 400 mol m 3 NaCl than in plants grown at 25 mol m−3 NaCl. Concentrations of Cr and of the sum of the cations in recently expanded tissue were similar to those in the bulk of the roots, consisting mainly of old cells. However, the K+: Na+ decreased with age; at 400 mol m−3 external NaCl with a K+: Na+ of 0.012, the K+: Na+ in recently expanded 12 mm root tips was as high as 1.6, compared with 0.7 for the bulk of the roots.These ion data were used to estimate cytoplasmic and vacuolar concentrations of K+ and Na +. Such calculations indicated that between 25 mol m3 and 400 mol m−3 external NaCl the concentration of the sum of (Na++K+) in the cytoplasm was maintained at about 180–200 mol m−3 (cell water basis). In contrast, the (Na++ K+) concentration in the vacuole was 170 mol m−3 for plants grown at 25 mol m−3 NaCl and 420 mol 400 mol m−3 NaCl.The expanding root (issues exhibited greatly decreased soluble sugars and starch between dusk and dawn. Ai both times, sugar and starch concentrations in these tissues were 2.5–4.0 times greater in plants grown at 400 mol m−3 NaCl compared with plants grown at 25 mol m−3 NaCl. In contrast, carbohydrate concentrations in expanded root tissues were very similar at 25 and 400 mol m−3 and showed little diurnal fluctuation.This paper considers the causes for the slower growth of A. amnicola at 400 than at 25 mol m”3 NaCl, using the data for the roots described here, and those for the shoots presented in the preceding paper (Aslam et al., 1986). There is no support for possible adverse effects by high internal ion concentrations. Instead, there may be deficiencies in supply of organic solutes for osmotic regulation; during part of the night a limited supply of such solutes may well restrict the rate of expansion of cells in plants growing at 400 mol m−3 NaCl. There is insufficient evidence to decide whether this limitation in the expanding tissues is particularly prominent for the roots or for the shoots.

Notes: Abstract. Aspects of the response of Kallar grass (Diplachne fusca) to root salinity have been studied. Field observation on the high level of tolerance of this species have been mirrored in pot trials and a 50% yield (dry matter) was obtained at ECe 22.3. While salt stress led to Na and Cl uptake, most of these ions appeared to be secreted selectively from the leaves. The shoot K+ content on a tissue water basis remained unaffected by salt stress and the shoot tissue had a high K+ selectivity. Osmotic adaptation was mainly brought about by tissue dehydration and not net salt accumulation although the compatible solute glycinebetaine was accumulated in fairly high concentrations.The organic and inorganic chemical composition of the shoots, including the trace elements Zn, Fe, Cu and Mn, is such as to make this species a highly promising plant for the exploitation of saline soils which might otherwise not be amenable to agriculture use.

Notes: Abstract Atriplex amnicola, was grown in nutrient solution cultures with concentrations of NaCl up to 750 mol m−3. The growth optimum was at 25–50 mol m−3 NaCl and growth was 10–15% of that value at 750 mol m−3 NaCl. Sodium chloride at 200 mol m−3 and higher reduced the rate of leaf extension and increased the time taken for a leaf to reach its maximal length.Concentrations of Na+, K+ and Mg2+ in leaves of different ages were investigated for plants grown at 25, 200 and 400 mol m−3 NaCl. Although leaves of plants grown at 200 and 400 mol m−3 NaCl had high Na+ concentrations at young developmental stages, much of this Na+ was located in the salt bladders. Leaves excluding bladders had low Na+ concentrations when young, but very high in Na+ when old.In contrast to Na+, K+ concentrations were similar in bladders and leaves excluding bladders. Concentrations of K+ were higher in the rapidly expanding than in the old leaves. At 400 mol m−3 NaCl, the K+:Na+ ratios of the leaves excluding bladders were 0.4–0.6 and 0.1 for rapidly expanding and oldest leaves, respectively. The Na+ content in moles per leaf, excluding bladders, increased linearly with the age of the leaves; concurrent increases in succulence were closely correlated with the Na + concentration in the leaves excluding the bladders.Soluble sugars and starch in leaves, stems and buds were determined at dusk and dawn.There was a pronounced diurnal fluctation in concentrations of carbohydrates. During the night, most plant parts showed large decreases in starch and sugar. Concentrations of carbohydrates in most plant organs were similar for plants grown at 25 and 400 mol m−3 NaCl. One notable exception was buds at dusk, where sugar and starch concentrations were 30–35% less in plants grown at 400 mol m−3 NaCl than in plants grown at 25 mol m−3 NaCl.The data indicate that the growth of A. amnicola at 400 mol m−3 NaCl is not limited by the availability of photosynthate in the plant as a whole. However, there could have been a growth limitation due to inadequate organic solutes for osmotic regulation.